BleepingComputer.com: DVD/RW problem with Vista

Hi,
I'm running Vista Home Premium on a Medion with a Quad 6600 CPU. I've tried two different LG DVD/RW drives both of which work fine on an old XP machine and read discs perfectly (including Adobe Lightroom and Starcraft II). On the Vista machine they 'read' these discs but don't autoplay and the apple icon appears. The DVD sees the disc as HST+ or unknown file format. Explorer gives a list of files but trying to open any file on the disc will crash explorer. They occasionally won't read the disc at all and will want to format it. I managed to put Lightroom onto my Vista computer by burning a copy using the XP machine. The dvd drive then read and installed this (though it didn't autorun).
I've trawled the Microsoft forums and tried various Microsoft 'Fix-It's. I've uninstalled and re-installed the drives and updated the firmware, I've bought a new dvd drive, all to no effect. The DVD drives will read CDs. I presume its a problem with the registry or a conflicting program? I rarely use the dvd drive to install games or to watch dvds, so I've no idea how far back I'd have to go to try system restore.
Any suggestions would be most welcome.
Thanks